Genomic Selection in Dairy Cattle

Dr.Wuttigrai Boonkum

Genomic Selection

• Dairy cattle most are specialised dairy breed Holstein, Jersey, Brown Swiss, Ayrshire• Some dual propose Simmental, Montbeliarde, Normande, etc• More than 80% AI from AI companies• Global exchange of genetic so international

genetic evaluation

Genomic Selection

P = G + EGenetic evaluation or Molecular genetics

Need time and data completeAppropriated major gene only

Genomic Selection,What does it bring us?

• Reliable breeding values at young age

– higher success rate to get top bulls

– lower costs for test proofs

– shorter generation-interval

Reliability of breeding values

Categorie Production Type Longevity

Parent average 35% 35% 30%

GS young bull 50-55% 45-50% 40-45%

1st EBV (prog.) 80% 75% 50-65%

2nd EBV (prog.) 89% 81% 50-80%

50% reliability is realistic

Advantages of Genomic Selection

• Increased genetic improvement (30-40%)

• Higher genetic level of test sires

• Higher genetic level of Delta embryo’s

• Wider portfolio of commercial bulls & higher level

• More outcross; less inbreeding

Disadvantages of Genomic Selection

• New method, not fully proven or tested

• Need to genotype a sufficiently large set of animals for accurate GEBV

• Across breed accuracy low• Genotypes still costly (10,000 bath/head)

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TMZ TF

Friebrah

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Dairy cattle crossbreds

Traits TF TMZ FB

Milk yield (kg/head/lactation)Milk yield (kg/head/day)Day in milk (day)First oestrus after calving (day)Calving interval (day)Number of service per conception (times)Income (baht/lactation)Production cost (baht/lactation)Milk production cost (baht/kg)Net profit (baht)

4,517.76+384.1914.39+2.92314.45+24

69.17+28415.10+722.10+0.8752,406.0129,795.39

6.3722,610.62

3,902.57+460.9113.34+4.06292.30+28

68.19+43399.90+491.70+0.8245,269.8728,032.08

7.4917,237.79

2,472.90+456.129.20+1.21

268.50+5154.23+28

363.70+431.40+0.6928,676.2424,646.17

9.914,030.07

Table 3 Comparison of average of milk yield, reproductive performance and economic returns of Thai Friesian (TF), Thai milking zebu (TMZ) and Friebrah (FB)

Source: (สดใส และค์ณะ, 2549 ก,ข)

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Selection indexincluding

MA information

medium, low

Heritability

high

BLUPBLUP

TraditionalSelection indexby MT-BLUP

Pre-selectionby markerconfirmed

by MT-BLUPindex

MASSelection indexby MA-BLUP

GΔ GΔGΔ

GΔ

Figure 6 Dairy cattle improvement using BLUP and genetic marker scheme